In the positive displacement rotary vane type of meter of pump described in the said copending applications, the yoke and vane assemblies are rotationally and reciprocably mounted on a shaft disposed in eccentric relationship to the axis of rotation of a hollow rotor in which the yoke and vanes are located. To assure that the vanes do not cock relative to the axis of the eccentric shaft, in that prior construction the vanes are secured to the yoke mechanisms at spaced apart locations.
In order to provide a device of this type which is sufficiently accurate to perform satisfactorily as a meter, close dimensional tolerances must be maintained to assure a proper fit between the vanes and the walls of the fluid chamber. Accordingly, the vanes have been fixed to the yoke members and each meter or pump has been custom fitted. Moreover, two different yoke members have been required for each meter or pump.